When
I was 12, a friend brought a telescope catalog to school. It was from
Celestron. It was the first time I'd ever heard of a
Schmidt-Cassegrain. I borrowed it, kept it for a couple of weeks,
read it cover to cover until I had large swaths of it memorized.

During research into retrofocally corrected refractor systems, I noted an effect during experiments with an optical bench cum telescope apparatus, that is, when the correcting flint element was removed from the train, the image recovery lenses still formed a back focus image which was smaller but seemed well corrected for colour, in fact it was a better correction than was being had with the flint lens in situ for that particular array